Safety device for avoiding back-firing in carburetors



Dec. 24, 1929. c. 'M. v. ALLENOU SAFETY DEVICE FOR AVOIDING BACK FIRING IN CARBURETORS Filed Dec. 17, 1926 l'xto/me/vr Patented Dec. 24, 1929 UNITED STATES CHARLES MARIE VICTOR ALLENOU, OF NANTES, FRANCE SAFETY DEVICE FOR AVOIDING BACK-FIRING IN CARBURETORS Application filed. December 17, 1926, Serial No. 155,518, and. in France'December 24, 1925-.

My present invention has for its object to provide an improved safety device designed for avoiding back-firing in explosion engines towards the carburetors thereof.

Devices of this character heretofore known generally comprise afiap-valve which is independent from the parts of the carburetor and urged by aspring towards its closed position, said valve being normally held apart from its seat by an easily fusible body.

In contradistinction to these known devices, my invention is characterized in that the member which upon the fusion of the fusible body cuts oi the supply of fuel, is formed of the spraying nozzle itself which will out off the supply of fuel by its own displacement.

My invention is illustrated by way of example in the accompanying drawings showing the application thereof to various types of carburetors.

Figure 1 is a sectional view illustrating one form of the invention.

Figures 2, 3 and 4 are similar views of different forms of the invention.

Figure 5 is a sectional view, partly in elevation, of a conventional carburetor illustrating the application of the invention thereto.

In Figure 1 the spraying nozzle 1 ends at its base into a cone-shaped portion 2. Said spraying nozzle 1, urged by a spring 6 bearing against a collar 7 is tightly held immovable in normal operation by a weld 3 of fusible metal or alloy, cast into a cylindrical depression 4 provided with ribs in the mass 5. Upon back-firing the heating of the spraying nozzle 1 will result into the fusion of the alloy 3, the nozzle will no longer be retained in its support 5 and by the action of the spring 6 it will be moved upwardly with its bevelled or cone-shaped end portion 2. Thus the latter will be brought upon its seat 8 and cut off the supply of fuel between the pipe 9 and inlet port 10.

Fig. 2 shows a modification wherein the spraying nozzle 11 having a bevelled or cone shaped lower end 12 and a spring 13, is tightly held in a corresponding recess in the mass 15 by a fusible and removable cone 14 compressed by a washer 16 locked on the nozzle 11 and aunt 17.-

Owing to the action of heat the liberated nozzle will cut off the supply as in the device previously described.

' Fig. 3 shows a carburetor with concentric spraying nozzles, the central nozzle 18 of which may be liberated for displacement upon the fusion'of an alloy. The nozzle 18 urged by a spring is slidable longitudinally in the centre of the main nozzle 19 whereby the bevelled or cone shaped end portion 20 thereof will be moved upwardly. Normally the nozzle 18 is held immovable by a removable fusible cone 21, tightly housed in a suitable recess in the top of the main nozzle 19 and retained therein by a collar 22. Said fusible cone is furthermore secured in place by the counterpressure exerted by a screw-threaded member 23 upon a washer 24:.

Upon the fusion of the cone 21 the upwardly moving nozzle 18 will bring its bevelled endportion 20 upon its seat to cut off the supply as previously.

As shown the fusible cones may be arranged either at the top (cone 21) or at the base (cone 25) ofthe main nozzle 19. Fig. 4 shows in normal operative position a'spraying nozzle 27 urged downwardly by a spring 28. Said nozzlehas a hole 29 for the admission of fuel and its bottom part ends into a tightly closing needle valve 30. The bottom part of said nozzle 27 is loosely surrounded by a sleeve 31 the lower part of which ends into a truncated portion 32 having an annular opening. Said sleeve 31 made integral with the nozzle 27 by means of a tight weld 35 of easily fusible metal, rests tightly with its bevelled part 32 on the orifice of a fuel supply pipe 33.

Upon the firing of fuel in the opening 34 produced by back firing, the nozzle 27 heated thereby will cause the fusion of the weld 35. As now the nozzle 27 is no longer retained by the sleeve 31, the same will slide within the latter and by the action of the spring 28 the needle valve 30 will close the annular opening in the truncated end 32, whereby the supply of fuel from the pipe 33 will be out off and if necessary, by slightly changing the diameter of said fuel pipe 33, the discharge opening thereof will be closed also.

Having now fully described my said invention, what I claim and desire to secure by Letters Patent, is:

1. In a safety device for avoiding back-firing towards the carburetor of; an explosion engine, the combination of a spraying nozzle normally immovable, an easily fusible metal holding said nozzle in place, a spring urging said nozzle towards the inlet of fuel, and means on the lower end of said nozzle capable of closing the inlet of fuel upon the liberation of said nozzle by the back-fire heat, substantially' as set forth.

2. In a safety device for avoiding backfi ing towards th c buretor of: an explosi n engine, the combination of a spraying nozzle normally immovable, an easily fusiblemetal holding said nozzle in place, a sprizl g urging said nozzle towards the inlet of; fuel, a boy, elled or cone-shapedportion thelower-end of said nozzle, and a valve seat in the fuel supply conduit cooperating with said-oom- Shaped P t n, ubs antial y and. or-tho purpose set forth.

In a saf ty evice o iding book.- firing towards the carburetor of an eirplosive e gine, h c bi ation f a spraying nozzle, a fixe or r part; th ough. whi h sai n l xt nds, a r s i fix d member, fusible metal in said recess to hol the nozzle n mally in place, a pr ng-urgi gsoid nozzle upwardly, a bevelled orv eonershaped portion at the lower end of sa d nozzle, anda valve seat in the fuel supply conduit i id o -shap d p r ion, substantially as and for the purpose set forth,

4. In a safety device 'for-avoidingahack firing towards the carburetor-,of an explosive.

engine, the combination of a sprayingnozzle, a fixed member or part through which said nozzle extends, a'recess in saidfi-xedmember, a truncated part of fusible. metal arranged on the nozzle in said recess, a spring urging the nozzle upwardly, a bevelled For; cone,-v op p rt on he l w road of. said oozzle, and a valve seat in the fuel supply conduit p r g wi h said one-shaped portion, substantially as and for; the purpose setforth.

In testimony whereof I have hereunto. set my hand.

HAR ES MARIE YIQTQR. ALLENQIL 

